1. Field of the Invention
This invention relates generally to electrical delay lines. More particularly, it relates to an electrical (i.e., non-mechanical) delay line capable of delaying a band of signals without significant distortion.
2. Background of Related Art
Delay lines are devices used by circuit designers to delay a particular signal input a predetermined amount of time before being output at an appropriate output port. Ideally, a delay line delays an input signal independent of the input frequency (i.e., is non-dispersive).
Conventional delay lines have been mechanically adjustable coaxial devices which typically insert a center conductor into an outer conductor a predetermined amount to provide the desired delay. Such delay lines having an adjustable transit time are typically called a "trombone". Unfortunately, mechanics in any circuit causes concern for reduced reliability and increased cost of manufacture.
Another conventional type of delay line has a plurality of taps, each tap having a predetermined delay associated therewith. However, multiple-tap delay lines suffer from interruptions in the signal and impedance caused by each of the various taps between the input and the chosen tap output.
There is a need for a delay line which does not suffer from the disadvantages inherent in conventional electromechanical or multiple-tap delay lines.